tdf#124743 TipOfTheDay: Next tip should not be random

A user pressing "next tip" will expect to cycle sequentially
through the list of tips, and not get a random one each time.

Change-Id: I331d35d623b6449a9daef407a498b4ba08eaff6f
Reviewed-on: https://gerrit.libreoffice.org/72099
Tested-by: Jenkins
Reviewed-by: Justin Luth <justin_luth@sil.org>
Reviewed-by: Heiko Tietze <tietze.heiko@gmail.com>

cui/source/dialogs/tipofthedaydlg.cxx

@@ -127,8 +127,8 @@ IMPL_LINK_NOARG(TipOfTheDayDialog, OnLinkClick, weld::LinkButton&, void)
 
 IMPL_LINK_NOARG(TipOfTheDayDialog, OnNextClick, weld::Button&, void)
 {
-    nCurrentTip = rand() % nNumberOfTips;
+    nCurrentTip = (nCurrentTip + 1) % nNumberOfTips;
     UpdateTip();
 }
 
-/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
\ No newline at end of file
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */